B/C Gap

Hylander · January 26, 2017, 06:18 PM

just received my new Uberti Smoke Wagon. 45 Colt.
B/C gap is. 007
seems excessive to me.
send it back?

jaguarxk120 · January 26, 2017, 06:25 PM

My new Cattleman 45 is .004, that's with a empty case in the chamber lined up with the barrel.

I have a older (21 yrs. old) Cattleman at the gunsmith to have the barrel cylinder gap reset, it was .012 gap.

nhyrum · January 26, 2017, 06:27 PM

For newer guns, anything over .004 is generally "excessive"

Watch for leading on the barrel face, that will tell you if it's truly excessive

Sent from my SM-G900V using Tapatalk

Snyper · January 26, 2017, 08:36 PM

I'd shoot it and not worry over it.
Dan Wessons are known for their accuracy and they use a .006 gap

Hylander · January 26, 2017, 09:24 PM

Rechecked, a .008 slides through

reddog81 · January 26, 2017, 09:47 PM

I think that .004 to .006 was ideal and up to .010 was acceptable. What's the end shake range?

I'd guess Uberti would consider .008 to be acceptable. You could contact them and see what they say.

Hylander · January 27, 2017, 12:38 AM

I called Taylors, left a message for the gun smith.
Will call again tomorrow to see if I an talk to Tom.

Pathfinder45 · January 27, 2017, 01:52 AM

I once had a very old and weathered Colt SAA 45 that had excessive and uneven B/C gap; the worst I've ever seen. But I'll be darned if it didn't shoot real well.

ShootistPRS · January 27, 2017, 06:15 PM

Measuring the cylinder gap requires the a case is in the firing position. If you check the gap without the case there it will and should be larger.

Hylander · January 29, 2017, 12:13 PM

Will be sending it back tomorrow though to see if they will tighten up
the B/C gap and the front sight is also canted.

**44 AMP** · January 29, 2017, 05:14 PM

A canted front sight would be a bigger issue for me. For a LONG time .006" was considered a good standard and +/- .002" was considered tolerable if the gun shot well. And for a LONG time, the smaller gap was less desirable, as it fouled faster when all the ammo was black powder.

Get the sight straight, then see how it shoots, and don't freak on .008" gap, if it shoots well.

**JohnKSa** · January 29, 2017, 05:30 PM

I believe that Kuhnhausen says that 0.006" is right for jacketed bullets and 0.008" is right for lubed lead bullets.

That's measured with the hammer back, as I recall.

Sounds like 0.008" would be ideal for a revolver when the manufacturer doesn't know for certain what type of ammo the buyer will use.

SaxonPig · January 29, 2017, 06:06 PM

I think you worry too much. I think .008" will work fine and would be considered within specifications. Too tight and it will start binding from carbon and residue build up. I'd rather have it fall on the reliable side of the scale.

Driftwood Johnson · January 29, 2017, 06:12 PM

Howdy

Yes, Kuhnhausen says that .006 is correct for jacketed bullets and .008 is correct for lubed leaded bullets.

However there is a little bit more to it than that. The correct way to measure barrel/cylinder gap is with the cylinder shoved forward. If there is any endshake (forward and backwards slop) endshake will mask the true b/c gap. That's why you make sure the cylinder is shoved all the way forward before running your shim stock through. Don't allow the shim stock to shove the cylinder backwards taking up the endshake. In theory there should be zero endshake, but that is not always true, a couple of thousandths of endshake is common.

For what it's worth, I have lots and lots of old revolvers. Some of them have gaps much larger than .008. None of them suffers much from accuracy that I can detect. When I buy an old revolver, I don't bring feeler gauges with me, I just eyeball the gap. I certainly would not sweat a gap of .007 or .008.

However I once owned a Cimarron Cattlman with a canted front sight, and I would not put up with that in a new gun.

jackmoser65 · January 29, 2017, 07:10 PM

The improper application of information gleaned from magazine articles has people worried over all sorts of things, getting out their expensive pin gauges and fretting over barrel cylinder gaps before they ever fire the first shot. Here's a not so subtle hint, shoot it first and determine if there actually is a problem before worrying about fixing it. It's not a Freedom Arms, just shoot the danged thing.

Driftwood Johnson · January 29, 2017, 11:31 PM

He said the front sight is also canted. That is a problem. As I said earlier I used to have an Uberti Cattleman with a canted front sight. I bought it used and did not notice until later that the front sight was leaning to one side. It had not been torqued in properly.

So even though the gap is not a problem, the front sight should be straight up and down. If I bought a brand new revolver I would expect the sight to be properly straight up and down.

Now I know to always make sure the front sight is straight up and down on a SAA type replica.

Hylander · January 30, 2017, 12:42 AM

The more I check the revolver the less I am worried about the gap.
However the front sight canted definitely has to addressed.
I am going to call their smith tomorrow morning and see if they want me to shoot it first to see how far off it is before it gets adjusted.

Hylander · February 10, 2017, 12:39 AM

Just got the email, my Smoke Wagon is on the way back

Should receive it Monday.
Not sure what they did or did not do, so keeping my fingers crossed.

Bamashooter · February 10, 2017, 12:59 AM

Isnt there a certain way to check the cylinder gap? For some reason Im thinking with the revolver cocked you pull and hold the trigger and check it then. Im not a huge revolver guy so Im not sure.

Driftwood Johnson · February 10, 2017, 11:06 AM

Quote:

Isnt there a certain way to check the cylinder gap? For some reason Im thinking with the revolver cocked you pull and hold the trigger and check it then. Im not a huge revolver guy so Im not sure.

See my answer in post #14 above. With a single action revolver, it does not matter if the hammer is cocked or down, but it is more convenient to measure the b/c gap with the hammer down. If there is endshake present, the cylinder will slide back and forth anyway. The cylinder should be shoved as far forward as possible to measure the b/c gap.

Hylander · February 16, 2017, 09:28 PM

So I received my Smoke Wagon back.
They changed the cylinder and now the Gap is .0035 which is great.
However now the cylinders serial numbers do not match the frame.
Also the chambers are under sized, on the original cylinder the chambers were perfect.
Send it back again or call it a day ?

Pathfinder45 · February 16, 2017, 10:16 PM

So, what are you calling undersized, that is, what are the measurements? Your original B/C gap was probably better for real black-powder ammo. But what's done is done. you can only move forward.

Hylander · February 16, 2017, 11:32 PM

.451

**JohnKSa** · February 17, 2017, 12:27 AM

Did they fix the front sight cant? That was really the only problem with the gun before you sent it in.

Quote:

They changed the cylinder and now the Gap is .0035 which is great.

Yeah, probably not really great, but hopefully workable if you don't plan to shoot it much in any given range session with lubed lead bullets. It was probably better before.

Hylander · February 17, 2017, 12:31 AM

Quote:

Did they fix the front sight cant? That was really the only problem with the gun before you sent it in.

They changed the cylinder and now the Gap is .0035 which is great.

Quote:

Yeah, probably not really great, but hopefully workable if you don't plan to shoot it much in any given range session with lubed lead bullets. It was probably better before.

Front sight looks straight now, have not shot it yet.
I am super happy with the .0035, I can always open it up a tad if need be, but I have never had an issue with binding with a small gap.
On the other hand I have had issues with a large gap (blow by).
I think I may keep it as is and send the cylinder out to have the chambers opened up to .4525

January 26, 2017, 08:36 PM	#4
Snyper Senior Member Join Date: December 16, 2013 Location: Eastern NC Posts: 3,047	I'd shoot it and not worry over it. Dan Wessons are known for their accuracy and they use a .006 gap __________________ One shot, one kill

January 26, 2017, 09:24 PM	#5
Hylander Senior Member Join Date: August 13, 2008 Location: California Posts: 128	Rechecked, a .008 slides through __________________ Today is my Best Day. Lincoln, Ca.

January 27, 2017, 12:38 AM	#7
Hylander Senior Member Join Date: August 13, 2008 Location: California Posts: 128	I called Taylors, left a message for the gun smith. Will call again tomorrow to see if I an talk to Tom. __________________ Today is my Best Day. Lincoln, Ca.

January 29, 2017, 12:13 PM	#10
Hylander Senior Member Join Date: August 13, 2008 Location: California Posts: 128	Will be sending it back tomorrow though to see if they will tighten up the B/C gap and the front sight is also canted. __________________ Today is my Best Day. Lincoln, Ca.

January 29, 2017, 05:14 PM	#11
44 AMP Staff Join Date: March 11, 2006 Location: Upper US Posts: 28,817	A canted front sight would be a bigger issue for me. For a LONG time .006" was considered a good standard and +/- .002" was considered tolerable if the gun shot well. And for a LONG time, the smaller gap was less desirable, as it fouled faster when all the ammo was black powder. Get the sight straight, then see how it shoots, and don't freak on .008" gap, if it shoots well. __________________ All else being equal (and it almost never is) bigger bullets tend to work better.

January 26, 2017, 06:18 PM	#1
Hylander Senior Member Join Date: August 13, 2008 Location: California Posts: 128	B/C Gap just received my new Uberti Smoke Wagon. 45 Colt. B/C gap is. 007 seems excessive to me. send it back? __________________ Today is my Best Day. Lincoln, Ca.

January 26, 2017, 06:25 PM	#2
jaguarxk120 Senior Member Join Date: February 28, 2008 Location: Michigan Posts: 2,619	My new Cattleman 45 is .004, that's with a empty case in the chamber lined up with the barrel. I have a older (21 yrs. old) Cattleman at the gunsmith to have the barrel cylinder gap reset, it was .012 gap.

January 26, 2017, 06:27 PM	#3
nhyrum Senior Member Join Date: March 9, 2016 Posts: 588	For newer guns, anything over .004 is generally "excessive" Watch for leading on the barrel face, that will tell you if it's truly excessive Sent from my SM-G900V using Tapatalk

January 26, 2017, 09:47 PM	#6
reddog81 Senior Member Join Date: October 16, 2014 Location: Iowa Posts: 1,634	I think that .004 to .006 was ideal and up to .010 was acceptable. What's the end shake range? I'd guess Uberti would consider .008 to be acceptable. You could contact them and see what they say.

January 27, 2017, 01:52 AM	#8
Pathfinder45 Senior Member Join Date: January 7, 2008 Posts: 3,224	I once had a very old and weathered Colt SAA 45 that had excessive and uneven B/C gap; the worst I've ever seen. But I'll be darned if it didn't shoot real well.

January 27, 2017, 06:15 PM	#9
ShootistPRS Senior Member Join Date: January 3, 2017 Posts: 1,583	Measuring the cylinder gap requires the a case is in the firing position. If you check the gap without the case there it will and should be larger.

January 29, 2017, 05:30 PM	#12
JohnKSa Staff Join Date: February 12, 2001 Location: DFW Area Posts: 24,972	I believe that Kuhnhausen says that 0.006" is right for jacketed bullets and 0.008" is right for lubed lead bullets. That's measured with the hammer back, as I recall. Sounds like 0.008" would be ideal for a revolver when the manufacturer doesn't know for certain what type of ammo the buyer will use. __________________ Do you know about the TEXAS State Rifle Association?

January 29, 2017, 06:06 PM	#13
SaxonPig Senior Member Join Date: April 24, 2006 Posts: 1,900	I think you worry too much. I think .008" will work fine and would be considered within specifications. Too tight and it will start binding from carbon and residue build up. I'd rather have it fall on the reliable side of the scale.

January 29, 2017, 06:12 PM	#14
Driftwood Johnson Senior Member Join Date: January 3, 2014 Location: Land of the Pilgrims Posts: 2,033	Howdy Yes, Kuhnhausen says that .006 is correct for jacketed bullets and .008 is correct for lubed leaded bullets. However there is a little bit more to it than that. The correct way to measure barrel/cylinder gap is with the cylinder shoved forward. If there is any endshake (forward and backwards slop) endshake will mask the true b/c gap. That's why you make sure the cylinder is shoved all the way forward before running your shim stock through. Don't allow the shim stock to shove the cylinder backwards taking up the endshake. In theory there should be zero endshake, but that is not always true, a couple of thousandths of endshake is common. For what it's worth, I have lots and lots of old revolvers. Some of them have gaps much larger than .008. None of them suffers much from accuracy that I can detect. When I buy an old revolver, I don't bring feeler gauges with me, I just eyeball the gap. I certainly would not sweat a gap of .007 or .008. However I once owned a Cimarron Cattlman with a canted front sight, and I would not put up with that in a new gun.

January 29, 2017, 07:10 PM	#15
jackmoser65 Senior Member Join Date: October 11, 2014 Posts: 754	The improper application of information gleaned from magazine articles has people worried over all sorts of things, getting out their expensive pin gauges and fretting over barrel cylinder gaps before they ever fire the first shot. Here's a not so subtle hint, shoot it first and determine if there actually is a problem before worrying about fixing it. It's not a Freedom Arms, just shoot the danged thing.

January 29, 2017, 11:31 PM	#16
Driftwood Johnson Senior Member Join Date: January 3, 2014 Location: Land of the Pilgrims Posts: 2,033	He said the front sight is also canted. That is a problem. As I said earlier I used to have an Uberti Cattleman with a canted front sight. I bought it used and did not notice until later that the front sight was leaning to one side. It had not been torqued in properly. So even though the gap is not a problem, the front sight should be straight up and down. If I bought a brand new revolver I would expect the sight to be properly straight up and down. Now I know to always make sure the front sight is straight up and down on a SAA type replica.

January 30, 2017, 12:42 AM	#17
Hylander Senior Member Join Date: August 13, 2008 Location: California Posts: 128	The more I check the revolver the less I am worried about the gap. However the front sight canted definitely has to addressed. I am going to call their smith tomorrow morning and see if they want me to shoot it first to see how far off it is before it gets adjusted. __________________ Today is my Best Day. Lincoln, Ca.

February 10, 2017, 12:39 AM	#18
Hylander Senior Member Join Date: August 13, 2008 Location: California Posts: 128	On the way back Just got the email, my Smoke Wagon is on the way back Should receive it Monday. Not sure what they did or did not do, so keeping my fingers crossed. __________________ Today is my Best Day. Lincoln, Ca.

February 10, 2017, 12:59 AM	#19
Bamashooter Senior Member Join Date: March 12, 2010 Posts: 1,860	Isnt there a certain way to check the cylinder gap? For some reason Im thinking with the revolver cocked you pull and hold the trigger and check it then. Im not a huge revolver guy so Im not sure.

February 16, 2017, 09:28 PM	#21
Hylander Senior Member Join Date: August 13, 2008 Location: California Posts: 128	So I received my Smoke Wagon back. They changed the cylinder and now the Gap is .0035 which is great. However now the cylinders serial numbers do not match the frame. Also the chambers are under sized, on the original cylinder the chambers were perfect. Send it back again or call it a day ? __________________ Today is my Best Day. Lincoln, Ca.

February 16, 2017, 10:16 PM	#22
Pathfinder45 Senior Member Join Date: January 7, 2008 Posts: 3,224	So, what are you calling undersized, that is, what are the measurements? Your original B/C gap was probably better for real black-powder ammo. But what's done is done. you can only move forward.

February 16, 2017, 11:32 PM	#23
Hylander Senior Member Join Date: August 13, 2008 Location: California Posts: 128	.451 __________________ Today is my Best Day. Lincoln, Ca.